Some actors enjoy spending a great amount of time explaining the minutiae of their latest role, but not Peter Mullan.

Asked how he'd describe Don Murston, his character in the new-two part drama Stonemouth, the Scot answers: "A father and a criminal. That's as much effort I can put into analysing him - he's a complex creature."

The series is the first TV adaptation of acclaimed author Iain Banks' work since his death from cancer in 2013. It focuses on Stewart Gilmour, played by Christian Cooke, who returns to his childhood town of Stonemouth for the funeral of his friend - and Don's son - Callum.

Stewart was run out of town a few years before by the criminal family of his then girlfriend Ellie (Charlotte Spencer), but is now forced to face his own misdoings, and inadvertently uncovers suspicious events surrounding Callum's death, which was believed to be a suicide.

Mullan's description of Don, who is also Ellie's father and the no-nonsense head of Stonemouth's most notorious criminal family, might be restrained, but he does note that Stewart should tread carefully.

"Anyone who doesn't mind killing someone, you should be wary of at least," remarks the 55-year-old, who admits it was good to be filming in Scotland once again.

"I've been working away a lot so it's nice to be back there to work. Also Davy Kane [Stonemouth's screenwriter], we go back a long way, so it's great to work with him."

While the Murstons enjoy an affluent lifestyle and, on the surface, seem to have it all, Mullan adds that they're just another dysfunctional family - and that's not all down to the patriarch.

"Most criminal families are utterly dysfunctional. I don't think he [Don] is the sole reason for it, though. In that kind of environment, you collaborate into what they've become. If you're the son or wife of somebody who makes his money through threatening others and through bullying, then you're colluding in the dysfunctionality."

The subject matter might be serious, but Mullan insists there was "a really lovely atmosphere" on set.

"I know everybody says that, but there genuinely was," adds the actor, whose credits also include War Horse, Top Of The Lake and Sunshine On Leith.

"Beautiful, lovely young actors - every one of them," he continues.

"Back in the day, I would have been less happy to see two English actors play two Scots. In fact, I wouldn't have done it, to be honest. But thankfully, since Bobby Carlyle, Ewan McGregor and Kevin McKidd, and obviously now James McAvoy, these great actors have proved you can play any part and not just Scottish.

"In the last 15-20 years, you've got Scots actors playing English characters with nobody raising an eyebrow and the other way around, so I don't have an issue with it. In fact, I was in awe of Christian and Charlotte, who were absolutely spot-on and had faultless Scottish accents."

He especially admired the efforts of 27-year-old Cooke, who stayed in accent 24/7. "He did it in the same way that Bobby did it when he played a Liverpudlian in Cracker, and Johnny Lee Miller did in Trainspotting. In fact, I never knew that Johnny was English - that came as quite a shock to me," says Mullan, laughing as he recalls filming the 1996 Danny Boyle classic, in which he also starred.

The praise has been mutual, and Cooke even described Mullan as one of his all-time acting heroes.

"So I heard, that was really kind of him," he says in response.

"Christian's excellent, he's open and bright and he knows how to enjoy himself on a TV set," Mullan continues. And that's something the father of three believes is important, in an industry where it's too easy to become self-absorbed.

"If you take everything way too seriously, which you tend to do when you're younger, you become calcified; you can't relax in a scene, you're rigid, emotionally and physically. And Christian's really got it, he knows how to have a laugh then slip into a scene.

"There's nothing to learn per se, it's understanding it. When people in the crew are shouting 'Action' around you, if you're unfamiliar with it, you feel on edge. If you're doing a love-making scene, it's absurd - you're lying in bed with somebody and trying to be intimate and someone's shouting, 'Sound! Turnover! Action!' It's not normal."

One of eight children, Mullan was born to a nurse and lab technician in Peterhead, Aberdeenshire, but grew up in Glasgow. He ran a little wild as a youngster, but began acting at university and appeared in various stage productions upon graduation before making the move to TV, landing roles in the likes of Your Cheatin' Heart and Taggart.

In 1991, he appeared in Ken Loach's Riff-Raff and four years later, Mel Gibson's Braveheart.

Then in 1998, he won Best Actor at the 1998 Cannes Film Festival, for his role in My Name Is Joe.

He's also written and directed three feature films; 1998's Orphans, 2002's The Magdalene Sisters, which saw him walk away from the Venice Film Festival with the top prize, and 2010's Neds.

"I hit a lot of brick walls," he explains of writing Neds, the hard-hitting film about a young lad who, abandoned by the system, teachers and his parents, becomes a thug.

"A lot of it was very close to how I was brought up and things that had happened to me, but then you come across the autobiographical wall. Just because it happened to you doesn't make it interesting."

For now, Mullan's film-making is on hold, while he focuses on work in front of the camera.

He's recently completed Quarry, a TV series filmed in New Orleans, and will hopefully be returning to his native soil to shoot a movie about golf, directed by Sean Connery's son, Jason.

"It's a lovely wee script, and we're shooting that in St Andrews," he reveals.

"I know nothing about golf, but I'm looking forward to it."

:: Stonemouth is a two-part drama beginning on BBC One on Monday, June 8